• 400 g (14 oz) hapuku, skin and bones removed, cut into five equal portions
• 12 nettle leaves, to garnish
• 1 tablespoon grapeseed oil, for frying

Nettle Purée

• 250 ml (9 fl oz/1 cup) chicken stock
• 500 g (1 lb 2 oz) nettle leaves or sweet potato leaves
• 3 sheets titanium-strength gelatine, bloomed
• 2 teaspoons butter
• pink salt

Toasted Rye Butter

• 100 g (3½ oz) malted rye
• 500 g (1 lb 2 oz/2 cups) thick (double) cream

To make the nettle purée, put the chicken stock and nettle leaves in a large saucepan over medium heat. Boil the leaves for 2–3 minutes until soft. Drain, reserving the stock, then put the leaves in a blender and blend to a purée. To achieve purée consistency, you may need to loosen with some of the reserved stock. Weigh out 250 g (9 oz) of purée, reserving any leftover for future use.

While the purée is still warm, add the softened gelatine and blend again, ensuring the gelatine has melted and is fully incorporated. Add the butter and season with salt. Pass the purée through a fine sieve to remove any grit then spread very thinly — about 2 mm (¹/₁₆ inch) — over a sheet of acetate. Carefully transfer the sheet to a baking tray and place the tray in the freezer until the spread is solid, a minimum of 1–2 hours. Once frozen, gently peel from the sheet of acetate and cut into 5–6 squares, roughly 8 cm (3¼ inch) square. Return to the freezer until ready to serve.

To make the toasted rye butter, infuse the malted rye into the cream by first bringing the cream to the boil in a saucepan over medium heat. Once boiled, remove from the heat, add the rye and set aside to cool. Strain the mixture into a food processor fitted with a paddle attachment and beat until stiffly whipped. Continue until the whipped cream collapses and separates into butterfat globules. The buttermilk will separate from the butter and slosh around the bowl. Line a clean sieve with muslin (cheesecloth), add the butter and place over a bowl for the buttermilk to drain. Turn out the butter into a medium frying pan and cook over medium heat, swirling constantly until the butter is a nut-brown colour. Drain, reserving the solids until ready to serve.

Preheat the oven to 180°C (350°F/Gas 4). Place a large, ovenproof frying pan over medium heat. Add the fish and caramelise very lightly on both sides. Remove from heat, top each piece of fish with 1 square of the frozen nettle purée then place in the oven to finish cooking for 4–6 minutes or until the fish has just cooked through and the nettle purée square has melted, giving the fish a nice even coating. As you pull the fish from the oven, top with some rye butter solids.

Shallow-fry the 12 nettle leaves in the grapeseed oil in a medium frying pan over high heat until crisp. Season generously with salt. To finish, place a piece of fish on each plate. Garnish with the fried nettle leaves and serve.